PRIOR CONCURRENT THERAPY: Biologic therapy: Concurrent epoetin alfa allowed Chemotherapy: No prior cytotoxic chemotherapy for prostate cancer No other concurrent chemotherapy Endocrine therapy: See Disease Characteristics At least 6 weeks since prior antiandrogen therapy At least 4 weeks since prior hormonal therapy (6 weeks for antiandrogens) for prostate cancer other than continued LHRH agonist No concurrent systemic corticosteroids No concurrent anticancer hormonal therapy Radiotherapy: At least 3 weeks since prior radiotherapy No prior palliative radiotherapy to more than one site No prior strontium chloride Sr 89 or samarium Sm 153 lexidronam pentasodium No concurrent radiotherapy Surgery: At least 3 weeks since prior surgery Other: At least 4 weeks since prior investigational agent No concurrent immunosuppressive agents No other concurrent investigational agent No concurrent enzyme-inducing anticonvulsants (carbamazepine, phenobarbital, phenytoin), ketoconazole, diltiazem, rifampin, terfenadine, cisapride, astemizole, or pimozide No concurrent megestrol acetate for appetite Concurrent bisphosphonates allowed